drivers/acpi/processor_idle.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * processor_idle - idle state submodule to the ACPI processor driver
   4  *
   5  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   6  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   7  *  Copyright (C) 2004, 2005 Dominik Brodowski <linux@brodo.de>
   8  *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
   9  *                      - Added processor hotplug support
  10  *  Copyright (C) 2005  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
  11  *                      - Added support for C3 on SMP
  12  */
  13 #define pr_fmt(fmt) "ACPI: " fmt
  14
  15 #include <linux/module.h>
  16 #include <linux/acpi.h>
  17 #include <linux/dmi.h>
  18 #include <linux/sched.h>       /* need_resched() */
  19 #include <linux/tick.h>
  20 #include <linux/cpuidle.h>
  21 #include <linux/cpu.h>
  22 #include <linux/minmax.h>
  23 #include <linux/perf_event.h>
  24 #include <acpi/processor.h>
  25 #include <linux/context_tracking.h>
  26
  27 /*
  28  * Include the apic definitions for x86 to have the APIC timer related defines
  29  * available also for UP (on SMP it gets magically included via linux/smp.h).
  30  * asm/acpi.h is not an option, as it would require more include magic. Also
  31  * creating an empty asm-ia64/apic.h would just trade pest vs. cholera.
  32  */
  33 #ifdef CONFIG_X86
  34 #include <asm/apic.h>
  35 #include <asm/cpu.h>
  36 #endif
  37
  38 #define ACPI_IDLE_STATE_START   (IS_ENABLED(CONFIG_ARCH_HAS_CPU_RELAX) ? 1 : 0)
  39
  40 static unsigned int max_cstate __read_mostly = ACPI_PROCESSOR_MAX_POWER;
  41 module_param(max_cstate, uint, 0400);
  42 static bool nocst __read_mostly;
  43 module_param(nocst, bool, 0400);
  44 static bool bm_check_disable __read_mostly;
  45 module_param(bm_check_disable, bool, 0400);
  46
  47 static unsigned int latency_factor __read_mostly = 2;
  48 module_param(latency_factor, uint, 0644);
  49
  50 static DEFINE_PER_CPU(struct cpuidle_device *, acpi_cpuidle_device);
  51
  52 struct cpuidle_driver acpi_idle_driver = {
  53         .name =         "acpi_idle",
  54         .owner =        THIS_MODULE,
  55 };
  56
  57 #ifdef CONFIG_ACPI_PROCESSOR_CSTATE
  58 static
  59 DEFINE_PER_CPU(struct acpi_processor_cx * [CPUIDLE_STATE_MAX], acpi_cstate);
  60
  61 static int disabled_by_idle_boot_param(void)
  62 {
  63         return boot_option_idle_override == IDLE_POLL ||
  64                 boot_option_idle_override == IDLE_HALT;
  65 }
  66
  67 /*
  68  * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
  69  * For now disable this. Probably a bug somewhere else.
  70  *
  71  * To skip this limit, boot/load with a large max_cstate limit.
  72  */
  73 static int set_max_cstate(const struct dmi_system_id *id)
  74 {
  75         if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
  76                 return 0;
  77
  78         pr_notice("%s detected - limiting to C%ld max_cstate."
  79                   " Override with \"processor.max_cstate=%d\"\n", id->ident,
  80                   (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);
  81
  82         max_cstate = (long)id->driver_data;
  83
  84         return 0;
  85 }
  86
  87 static const struct dmi_system_id processor_power_dmi_table[] = {
  88         { set_max_cstate, "Clevo 5600D", {
  89           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
  90           DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},
  91          (void *)2},
  92         { set_max_cstate, "Pavilion zv5000", {
  93           DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
  94           DMI_MATCH(DMI_PRODUCT_NAME,"Pavilion zv5000 (DS502A#ABA)")},
  95          (void *)1},
  96         { set_max_cstate, "Asus L8400B", {
  97           DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
  98           DMI_MATCH(DMI_PRODUCT_NAME,"L8400B series Notebook PC")},
  99          (void *)1},
 100         {},
 101 };
 102
 103
 104 /*
 105  * Callers should disable interrupts before the call and enable
 106  * interrupts after return.
 107  */
 108 static void __cpuidle acpi_safe_halt(void)
 109 {
 110         if (!tif_need_resched()) {
 111                 raw_safe_halt();
 112                 raw_local_irq_disable();
 113         }
 114 }
 115
 116 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 117
 118 /*
 119  * Some BIOS implementations switch to C3 in the published C2 state.
 120  * This seems to be a common problem on AMD boxen, but other vendors
 121  * are affected too. We pick the most conservative approach: we assume
 122  * that the local APIC stops in both C2 and C3.
 123  */
 124 static void lapic_timer_check_state(int state, struct acpi_processor *pr,
 125                                    struct acpi_processor_cx *cx)
 126 {
 127         struct acpi_processor_power *pwr = &pr->power;
 128         u8 type = local_apic_timer_c2_ok ? ACPI_STATE_C3 : ACPI_STATE_C2;
 129
 130         if (cpu_has(&cpu_data(pr->id), X86_FEATURE_ARAT))
 131                 return;
 132
 133         if (boot_cpu_has_bug(X86_BUG_AMD_APIC_C1E))
 134                 type = ACPI_STATE_C1;
 135
 136         /*
 137          * Check, if one of the previous states already marked the lapic
 138          * unstable
 139          */
 140         if (pwr->timer_broadcast_on_state < state)
 141                 return;
 142
 143         if (cx->type >= type)
 144                 pr->power.timer_broadcast_on_state = state;
 145 }
 146
 147 static void __lapic_timer_propagate_broadcast(void *arg)
 148 {
 149         struct acpi_processor *pr = arg;
 150
 151         if (pr->power.timer_broadcast_on_state < INT_MAX)
 152                 tick_broadcast_enable();
 153         else
 154                 tick_broadcast_disable();
 155 }
 156
 157 static void lapic_timer_propagate_broadcast(struct acpi_processor *pr)
 158 {
 159         smp_call_function_single(pr->id, __lapic_timer_propagate_broadcast,
 160                                  (void *)pr, 1);
 161 }
 162
 163 /* Power(C) State timer broadcast control */
 164 static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
 165                                         struct acpi_processor_cx *cx)
 166 {
 167         return cx - pr->power.states >= pr->power.timer_broadcast_on_state;
 168 }
 169
 170 #else
 171
 172 static void lapic_timer_check_state(int state, struct acpi_processor *pr,
 173                                    struct acpi_processor_cx *cstate) { }
 174 static void lapic_timer_propagate_broadcast(struct acpi_processor *pr) { }
 175
 176 static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
 177                                         struct acpi_processor_cx *cx)
 178 {
 179         return false;
 180 }
 181
 182 #endif
 183
 184 #if defined(CONFIG_X86)
 185 static void tsc_check_state(int state)
 186 {
 187         switch (boot_cpu_data.x86_vendor) {
 188         case X86_VENDOR_HYGON:
 189         case X86_VENDOR_AMD:
 190         case X86_VENDOR_INTEL:
 191         case X86_VENDOR_CENTAUR:
 192         case X86_VENDOR_ZHAOXIN:
 193                 /*
 194                  * AMD Fam10h TSC will tick in all
 195                  * C/P/S0/S1 states when this bit is set.
 196                  */
 197                 if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
 198                         return;
 199                 fallthrough;
 200         default:
 201                 /* TSC could halt in idle, so notify users */
 202                 if (state > ACPI_STATE_C1)
 203                         mark_tsc_unstable("TSC halts in idle");
 204         }
 205 }
 206 #else
 207 static void tsc_check_state(int state) { return; }
 208 #endif
 209
 210 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
 211 {
 212
 213         if (!pr->pblk)
 214                 return -ENODEV;
 215
 216         /* if info is obtained from pblk/fadt, type equals state */
 217         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 218         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 219
 220 #ifndef CONFIG_HOTPLUG_CPU
 221         /*
 222          * Check for P_LVL2_UP flag before entering C2 and above on
 223          * an SMP system.
 224          */
 225         if ((num_online_cpus() > 1) &&
 226             !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
 227                 return -ENODEV;
 228 #endif
 229
 230         /* determine C2 and C3 address from pblk */
 231         pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
 232         pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
 233
 234         /* determine latencies from FADT */
 235         pr->power.states[ACPI_STATE_C2].latency = acpi_gbl_FADT.c2_latency;
 236         pr->power.states[ACPI_STATE_C3].latency = acpi_gbl_FADT.c3_latency;
 237
 238         /*
 239          * FADT specified C2 latency must be less than or equal to
 240          * 100 microseconds.
 241          */
 242         if (acpi_gbl_FADT.c2_latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
 243                 acpi_handle_debug(pr->handle, "C2 latency too large [%d]\n",
 244                                   acpi_gbl_FADT.c2_latency);
 245                 /* invalidate C2 */
 246                 pr->power.states[ACPI_STATE_C2].address = 0;
 247         }
 248
 249         /*
 250          * FADT supplied C3 latency must be less than or equal to
 251          * 1000 microseconds.
 252          */
 253         if (acpi_gbl_FADT.c3_latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
 254                 acpi_handle_debug(pr->handle, "C3 latency too large [%d]\n",
 255                                   acpi_gbl_FADT.c3_latency);
 256                 /* invalidate C3 */
 257                 pr->power.states[ACPI_STATE_C3].address = 0;
 258         }
 259
 260         acpi_handle_debug(pr->handle, "lvl2[0x%08x] lvl3[0x%08x]\n",
 261                           pr->power.states[ACPI_STATE_C2].address,
 262                           pr->power.states[ACPI_STATE_C3].address);
 263
 264         snprintf(pr->power.states[ACPI_STATE_C2].desc,
 265                          ACPI_CX_DESC_LEN, "ACPI P_LVL2 IOPORT 0x%x",
 266                          pr->power.states[ACPI_STATE_C2].address);
 267         snprintf(pr->power.states[ACPI_STATE_C3].desc,
 268                          ACPI_CX_DESC_LEN, "ACPI P_LVL3 IOPORT 0x%x",
 269                          pr->power.states[ACPI_STATE_C3].address);
 270
 271         return 0;
 272 }
 273
 274 static int acpi_processor_get_power_info_default(struct acpi_processor *pr)
 275 {
 276         if (!pr->power.states[ACPI_STATE_C1].valid) {
 277                 /* set the first C-State to C1 */
 278                 /* all processors need to support C1 */
 279                 pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 280                 pr->power.states[ACPI_STATE_C1].valid = 1;
 281                 pr->power.states[ACPI_STATE_C1].entry_method = ACPI_CSTATE_HALT;
 282
 283                 snprintf(pr->power.states[ACPI_STATE_C1].desc,
 284                          ACPI_CX_DESC_LEN, "ACPI HLT");
 285         }
 286         /* the C0 state only exists as a filler in our array */
 287         pr->power.states[ACPI_STATE_C0].valid = 1;
 288         return 0;
 289 }
 290
 291 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
 292 {
 293         int ret;
 294
 295         if (nocst)
 296                 return -ENODEV;
 297
 298         ret = acpi_processor_evaluate_cst(pr->handle, pr->id, &pr->power);
 299         if (ret)
 300                 return ret;
 301
 302         if (!pr->power.count)
 303                 return -EFAULT;
 304
 305         pr->flags.has_cst = 1;
 306         return 0;
 307 }
 308
 309 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
 310                                            struct acpi_processor_cx *cx)
 311 {
 312         static int bm_check_flag = -1;
 313         static int bm_control_flag = -1;
 314
 315
 316         if (!cx->address)
 317                 return;
 318
 319         /*
 320          * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
 321          * DMA transfers are used by any ISA device to avoid livelock.
 322          * Note that we could disable Type-F DMA (as recommended by
 323          * the erratum), but this is known to disrupt certain ISA
 324          * devices thus we take the conservative approach.
 325          */
 326         if (errata.piix4.fdma) {
 327                 acpi_handle_debug(pr->handle,
 328                                   "C3 not supported on PIIX4 with Type-F DMA\n");
 329                 return;
 330         }
 331
 332         /* All the logic here assumes flags.bm_check is same across all CPUs */
 333         if (bm_check_flag == -1) {
 334                 /* Determine whether bm_check is needed based on CPU  */
 335                 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
 336                 bm_check_flag = pr->flags.bm_check;
 337                 bm_control_flag = pr->flags.bm_control;
 338         } else {
 339                 pr->flags.bm_check = bm_check_flag;
 340                 pr->flags.bm_control = bm_control_flag;
 341         }
 342
 343         if (pr->flags.bm_check) {
 344                 if (!pr->flags.bm_control) {
 345                         if (pr->flags.has_cst != 1) {
 346                                 /* bus mastering control is necessary */
 347                                 acpi_handle_debug(pr->handle,
 348                                                   "C3 support requires BM control\n");
 349                                 return;
 350                         } else {
 351                                 /* Here we enter C3 without bus mastering */
 352                                 acpi_handle_debug(pr->handle,
 353                                                   "C3 support without BM control\n");
 354                         }
 355                 }
 356         } else {
 357                 /*
 358                  * WBINVD should be set in fadt, for C3 state to be
 359                  * supported on when bm_check is not required.
 360                  */
 361                 if (!(acpi_gbl_FADT.flags & ACPI_FADT_WBINVD)) {
 362                         acpi_handle_debug(pr->handle,
 363                                           "Cache invalidation should work properly"
 364                                           " for C3 to be enabled on SMP systems\n");
 365                         return;
 366                 }
 367         }
 368
 369         /*
 370          * Otherwise we've met all of our C3 requirements.
 371          * Normalize the C3 latency to expidite policy.  Enable
 372          * checking of bus mastering status (bm_check) so we can
 373          * use this in our C3 policy
 374          */
 375         cx->valid = 1;
 376
 377         /*
 378          * On older chipsets, BM_RLD needs to be set
 379          * in order for Bus Master activity to wake the
 380          * system from C3.  Newer chipsets handle DMA
 381          * during C3 automatically and BM_RLD is a NOP.
 382          * In either case, the proper way to
 383          * handle BM_RLD is to set it and leave it set.
 384          */
 385         acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
 386 }
 387
 388 static void acpi_cst_latency_sort(struct acpi_processor_cx *states, size_t length)
 389 {
 390         int i, j, k;
 391
 392         for (i = 1; i < length; i++) {
 393                 if (!states[i].valid)
 394                         continue;
 395
 396                 for (j = i - 1, k = i; j >= 0; j--) {
 397                         if (!states[j].valid)
 398                                 continue;
 399
 400                         if (states[j].latency > states[k].latency)
 401                                 swap(states[j].latency, states[k].latency);
 402
 403                         k = j;
 404                 }
 405         }
 406 }
 407
 408 static int acpi_processor_power_verify(struct acpi_processor *pr)
 409 {
 410         unsigned int i;
 411         unsigned int working = 0;
 412         unsigned int last_latency = 0;
 413         unsigned int last_type = 0;
 414         bool buggy_latency = false;
 415
 416         pr->power.timer_broadcast_on_state = INT_MAX;
 417
 418         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
 419                 struct acpi_processor_cx *cx = &pr->power.states[i];
 420
 421                 switch (cx->type) {
 422                 case ACPI_STATE_C1:
 423                         cx->valid = 1;
 424                         break;
 425
 426                 case ACPI_STATE_C2:
 427                         if (!cx->address)
 428                                 break;
 429                         cx->valid = 1;
 430                         break;
 431
 432                 case ACPI_STATE_C3:
 433                         acpi_processor_power_verify_c3(pr, cx);
 434                         break;
 435                 }
 436                 if (!cx->valid)
 437                         continue;
 438                 if (cx->type >= last_type && cx->latency < last_latency)
 439                         buggy_latency = true;
 440                 last_latency = cx->latency;
 441                 last_type = cx->type;
 442
 443                 lapic_timer_check_state(i, pr, cx);
 444                 tsc_check_state(cx->type);
 445                 working++;
 446         }
 447
 448         if (buggy_latency) {
 449                 pr_notice("FW issue: working around C-state latencies out of order\n");
 450                 acpi_cst_latency_sort(&pr->power.states[1], max_cstate);
 451         }
 452
 453         lapic_timer_propagate_broadcast(pr);
 454
 455         return working;
 456 }
 457
 458 static int acpi_processor_get_cstate_info(struct acpi_processor *pr)
 459 {
 460         unsigned int i;
 461         int result;
 462
 463
 464         /* NOTE: the idle thread may not be running while calling
 465          * this function */
 466
 467         /* Zero initialize all the C-states info. */
 468         memset(pr->power.states, 0, sizeof(pr->power.states));
 469
 470         result = acpi_processor_get_power_info_cst(pr);
 471         if (result == -ENODEV)
 472                 result = acpi_processor_get_power_info_fadt(pr);
 473
 474         if (result)
 475                 return result;
 476
 477         acpi_processor_get_power_info_default(pr);
 478
 479         pr->power.count = acpi_processor_power_verify(pr);
 480
 481         /*
 482          * if one state of type C2 or C3 is available, mark this
 483          * CPU as being "idle manageable"
 484          */
 485         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 486                 if (pr->power.states[i].valid) {
 487                         pr->power.count = i;
 488                         pr->flags.power = 1;
 489                 }
 490         }
 491
 492         return 0;
 493 }
 494
 495 /**
 496  * acpi_idle_bm_check - checks if bus master activity was detected
 497  */
 498 static int acpi_idle_bm_check(void)
 499 {
 500         u32 bm_status = 0;
 501
 502         if (bm_check_disable)
 503                 return 0;
 504
 505         acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
 506         if (bm_status)
 507                 acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
 508         /*
 509          * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
 510          * the true state of bus mastering activity; forcing us to
 511          * manually check the BMIDEA bit of each IDE channel.
 512          */
 513         else if (errata.piix4.bmisx) {
 514                 if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
 515                     || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
 516                         bm_status = 1;
 517         }
 518         return bm_status;
 519 }
 520
 521 static __cpuidle void io_idle(unsigned long addr)
 522 {
 523         /* IO port based C-state */
 524         inb(addr);
 525
 526 #ifdef  CONFIG_X86
 527         /* No delay is needed if we are in guest */
 528         if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
 529                 return;
 530         /*
 531          * Modern (>=Nehalem) Intel systems use ACPI via intel_idle,
 532          * not this code.  Assume that any Intel systems using this
 533          * are ancient and may need the dummy wait.  This also assumes
 534          * that the motivating chipset issue was Intel-only.
 535          */
 536         if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
 537                 return;
 538 #endif
 539         /*
 540          * Dummy wait op - must do something useless after P_LVL2 read
 541          * because chipsets cannot guarantee that STPCLK# signal gets
 542          * asserted in time to freeze execution properly
 543          *
 544          * This workaround has been in place since the original ACPI
 545          * implementation was merged, circa 2002.
 546          *
 547          * If a profile is pointing to this instruction, please first
 548          * consider moving your system to a more modern idle
 549          * mechanism.
 550          */
 551         inl(acpi_gbl_FADT.xpm_timer_block.address);
 552 }
 553
 554 /**
 555  * acpi_idle_do_entry - enter idle state using the appropriate method
 556  * @cx: cstate data
 557  *
 558  * Caller disables interrupt before call and enables interrupt after return.
 559  */
 560 static void __cpuidle acpi_idle_do_entry(struct acpi_processor_cx *cx)
 561 {
 562         perf_lopwr_cb(true);
 563
 564         if (cx->entry_method == ACPI_CSTATE_FFH) {
 565                 /* Call into architectural FFH based C-state */
 566                 acpi_processor_ffh_cstate_enter(cx);
 567         } else if (cx->entry_method == ACPI_CSTATE_HALT) {
 568                 acpi_safe_halt();
 569         } else {
 570                 io_idle(cx->address);
 571         }
 572
 573         perf_lopwr_cb(false);
 574 }
 575
 576 /**
 577  * acpi_idle_play_dead - enters an ACPI state for long-term idle (i.e. off-lining)
 578  * @dev: the target CPU
 579  * @index: the index of suggested state
 580  */
 581 static int acpi_idle_play_dead(struct cpuidle_device *dev, int index)
 582 {
 583         struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 584
 585         ACPI_FLUSH_CPU_CACHE();
 586
 587         while (1) {
 588
 589                 if (cx->entry_method == ACPI_CSTATE_HALT)
 590                         raw_safe_halt();
 591                 else if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) {
 592                         io_idle(cx->address);
 593                 } else
 594                         return -ENODEV;
 595         }
 596
 597         /* Never reached */
 598         return 0;
 599 }
 600
 601 static __always_inline bool acpi_idle_fallback_to_c1(struct acpi_processor *pr)
 602 {
 603         return IS_ENABLED(CONFIG_HOTPLUG_CPU) && !pr->flags.has_cst &&
 604                 !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED);
 605 }
 606
 607 static int c3_cpu_count;
 608 static DEFINE_RAW_SPINLOCK(c3_lock);
 609
 610 /**
 611  * acpi_idle_enter_bm - enters C3 with proper BM handling
 612  * @drv: cpuidle driver
 613  * @pr: Target processor
 614  * @cx: Target state context
 615  * @index: index of target state
 616  */
 617 static int __cpuidle acpi_idle_enter_bm(struct cpuidle_driver *drv,
 618                                struct acpi_processor *pr,
 619                                struct acpi_processor_cx *cx,
 620                                int index)
 621 {
 622         static struct acpi_processor_cx safe_cx = {
 623                 .entry_method = ACPI_CSTATE_HALT,
 624         };
 625
 626         /*
 627          * disable bus master
 628          * bm_check implies we need ARB_DIS
 629          * bm_control implies whether we can do ARB_DIS
 630          *
 631          * That leaves a case where bm_check is set and bm_control is not set.
 632          * In that case we cannot do much, we enter C3 without doing anything.
 633          */
 634         bool dis_bm = pr->flags.bm_control;
 635
 636         instrumentation_begin();
 637
 638         /* If we can skip BM, demote to a safe state. */
 639         if (!cx->bm_sts_skip && acpi_idle_bm_check()) {
 640                 dis_bm = false;
 641                 index = drv->safe_state_index;
 642                 if (index >= 0) {
 643                         cx = this_cpu_read(acpi_cstate[index]);
 644                 } else {
 645                         cx = &safe_cx;
 646                         index = -EBUSY;
 647                 }
 648         }
 649
 650         if (dis_bm) {
 651                 raw_spin_lock(&c3_lock);
 652                 c3_cpu_count++;
 653                 /* Disable bus master arbitration when all CPUs are in C3 */
 654                 if (c3_cpu_count == num_online_cpus())
 655                         acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 1);
 656                 raw_spin_unlock(&c3_lock);
 657         }
 658
 659         ct_cpuidle_enter();
 660
 661         acpi_idle_do_entry(cx);
 662
 663         ct_cpuidle_exit();
 664
 665         /* Re-enable bus master arbitration */
 666         if (dis_bm) {
 667                 raw_spin_lock(&c3_lock);
 668                 acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 0);
 669                 c3_cpu_count--;
 670                 raw_spin_unlock(&c3_lock);
 671         }
 672
 673         instrumentation_end();
 674
 675         return index;
 676 }
 677
 678 static int __cpuidle acpi_idle_enter(struct cpuidle_device *dev,
 679                            struct cpuidle_driver *drv, int index)
 680 {
 681         struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 682         struct acpi_processor *pr;
 683
 684         pr = __this_cpu_read(processors);
 685         if (unlikely(!pr))
 686                 return -EINVAL;
 687
 688         if (cx->type != ACPI_STATE_C1) {
 689                 if (cx->type == ACPI_STATE_C3 && pr->flags.bm_check)
 690                         return acpi_idle_enter_bm(drv, pr, cx, index);
 691
 692                 /* C2 to C1 demotion. */
 693                 if (acpi_idle_fallback_to_c1(pr) && num_online_cpus() > 1) {
 694                         index = ACPI_IDLE_STATE_START;
 695                         cx = per_cpu(acpi_cstate[index], dev->cpu);
 696                 }
 697         }
 698
 699         if (cx->type == ACPI_STATE_C3)
 700                 ACPI_FLUSH_CPU_CACHE();
 701
 702         acpi_idle_do_entry(cx);
 703
 704         return index;
 705 }
 706
 707 static int __cpuidle acpi_idle_enter_s2idle(struct cpuidle_device *dev,
 708                                   struct cpuidle_driver *drv, int index)
 709 {
 710         struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 711
 712         if (cx->type == ACPI_STATE_C3) {
 713                 struct acpi_processor *pr = __this_cpu_read(processors);
 714
 715                 if (unlikely(!pr))
 716                         return 0;
 717
 718                 if (pr->flags.bm_check) {
 719                         u8 bm_sts_skip = cx->bm_sts_skip;
 720
 721                         /* Don't check BM_STS, do an unconditional ARB_DIS for S2IDLE */
 722                         cx->bm_sts_skip = 1;
 723                         acpi_idle_enter_bm(drv, pr, cx, index);
 724                         cx->bm_sts_skip = bm_sts_skip;
 725
 726                         return 0;
 727                 } else {
 728                         ACPI_FLUSH_CPU_CACHE();
 729                 }
 730         }
 731         acpi_idle_do_entry(cx);
 732
 733         return 0;
 734 }
 735
 736 static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
 737                                            struct cpuidle_device *dev)
 738 {
 739         int i, count = ACPI_IDLE_STATE_START;
 740         struct acpi_processor_cx *cx;
 741         struct cpuidle_state *state;
 742
 743         if (max_cstate == 0)
 744                 max_cstate = 1;
 745
 746         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
 747                 state = &acpi_idle_driver.states[count];
 748                 cx = &pr->power.states[i];
 749
 750                 if (!cx->valid)
 751                         continue;
 752
 753                 per_cpu(acpi_cstate[count], dev->cpu) = cx;
 754
 755                 if (lapic_timer_needs_broadcast(pr, cx))
 756                         state->flags |= CPUIDLE_FLAG_TIMER_STOP;
 757
 758                 if (cx->type == ACPI_STATE_C3) {
 759                         state->flags |= CPUIDLE_FLAG_TLB_FLUSHED;
 760                         if (pr->flags.bm_check)
 761                                 state->flags |= CPUIDLE_FLAG_RCU_IDLE;
 762                 }
 763
 764                 count++;
 765                 if (count == CPUIDLE_STATE_MAX)
 766                         break;
 767         }
 768
 769         if (!count)
 770                 return -EINVAL;
 771
 772         return 0;
 773 }
 774
 775 static int acpi_processor_setup_cstates(struct acpi_processor *pr)
 776 {
 777         int i, count;
 778         struct acpi_processor_cx *cx;
 779         struct cpuidle_state *state;
 780         struct cpuidle_driver *drv = &acpi_idle_driver;
 781
 782         if (max_cstate == 0)
 783                 max_cstate = 1;
 784
 785         if (IS_ENABLED(CONFIG_ARCH_HAS_CPU_RELAX)) {
 786                 cpuidle_poll_state_init(drv);
 787                 count = 1;
 788         } else {
 789                 count = 0;
 790         }
 791
 792         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
 793                 cx = &pr->power.states[i];
 794
 795                 if (!cx->valid)
 796                         continue;
 797
 798                 state = &drv->states[count];
 799                 snprintf(state->name, CPUIDLE_NAME_LEN, "C%d", i);
 800                 strscpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);
 801                 state->exit_latency = cx->latency;
 802                 state->target_residency = cx->latency * latency_factor;
 803                 state->enter = acpi_idle_enter;
 804
 805                 state->flags = 0;
 806                 if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2 ||
 807                     cx->type == ACPI_STATE_C3) {
 808                         state->enter_dead = acpi_idle_play_dead;
 809                         if (cx->type != ACPI_STATE_C3)
 810                                 drv->safe_state_index = count;
 811                 }
 812                 /*
 813                  * Halt-induced C1 is not good for ->enter_s2idle, because it
 814                  * re-enables interrupts on exit.  Moreover, C1 is generally not
 815                  * particularly interesting from the suspend-to-idle angle, so
 816                  * avoid C1 and the situations in which we may need to fall back
 817                  * to it altogether.
 818                  */
 819                 if (cx->type != ACPI_STATE_C1 && !acpi_idle_fallback_to_c1(pr))
 820                         state->enter_s2idle = acpi_idle_enter_s2idle;
 821
 822                 count++;
 823                 if (count == CPUIDLE_STATE_MAX)
 824                         break;
 825         }
 826
 827         drv->state_count = count;
 828
 829         if (!count)
 830                 return -EINVAL;
 831
 832         return 0;
 833 }
 834
 835 static inline void acpi_processor_cstate_first_run_checks(void)
 836 {
 837         static int first_run;
 838
 839         if (first_run)
 840                 return;
 841         dmi_check_system(processor_power_dmi_table);
 842         max_cstate = acpi_processor_cstate_check(max_cstate);
 843         if (max_cstate < ACPI_C_STATES_MAX)
 844                 pr_notice("processor limited to max C-state %d\n", max_cstate);
 845
 846         first_run++;
 847
 848         if (nocst)
 849                 return;
 850
 851         acpi_processor_claim_cst_control();
 852 }
 853 #else
 854
 855 static inline int disabled_by_idle_boot_param(void) { return 0; }
 856 static inline void acpi_processor_cstate_first_run_checks(void) { }
 857 static int acpi_processor_get_cstate_info(struct acpi_processor *pr)
 858 {
 859         return -ENODEV;
 860 }
 861
 862 static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
 863                                            struct cpuidle_device *dev)
 864 {
 865         return -EINVAL;
 866 }
 867
 868 static int acpi_processor_setup_cstates(struct acpi_processor *pr)
 869 {
 870         return -EINVAL;
 871 }
 872
 873 #endif /* CONFIG_ACPI_PROCESSOR_CSTATE */
 874
 875 struct acpi_lpi_states_array {
 876         unsigned int size;
 877         unsigned int composite_states_size;
 878         struct acpi_lpi_state *entries;
 879         struct acpi_lpi_state *composite_states[ACPI_PROCESSOR_MAX_POWER];
 880 };
 881
 882 static int obj_get_integer(union acpi_object *obj, u32 *value)
 883 {
 884         if (obj->type != ACPI_TYPE_INTEGER)
 885                 return -EINVAL;
 886
 887         *value = obj->integer.value;
 888         return 0;
 889 }
 890
 891 static int acpi_processor_evaluate_lpi(acpi_handle handle,
 892                                        struct acpi_lpi_states_array *info)
 893 {
 894         acpi_status status;
 895         int ret = 0;
 896         int pkg_count, state_idx = 1, loop;
 897         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 898         union acpi_object *lpi_data;
 899         struct acpi_lpi_state *lpi_state;
 900
 901         status = acpi_evaluate_object(handle, "_LPI", NULL, &buffer);
 902         if (ACPI_FAILURE(status)) {
 903                 acpi_handle_debug(handle, "No _LPI, giving up\n");
 904                 return -ENODEV;
 905         }
 906
 907         lpi_data = buffer.pointer;
 908
 909         /* There must be at least 4 elements = 3 elements + 1 package */
 910         if (!lpi_data || lpi_data->type != ACPI_TYPE_PACKAGE ||
 911             lpi_data->package.count < 4) {
 912                 pr_debug("not enough elements in _LPI\n");
 913                 ret = -ENODATA;
 914                 goto end;
 915         }
 916
 917         pkg_count = lpi_data->package.elements[2].integer.value;
 918
 919         /* Validate number of power states. */
 920         if (pkg_count < 1 || pkg_count != lpi_data->package.count - 3) {
 921                 pr_debug("count given by _LPI is not valid\n");
 922                 ret = -ENODATA;
 923                 goto end;
 924         }
 925
 926         lpi_state = kcalloc(pkg_count, sizeof(*lpi_state), GFP_KERNEL);
 927         if (!lpi_state) {
 928                 ret = -ENOMEM;
 929                 goto end;
 930         }
 931
 932         info->size = pkg_count;
 933         info->entries = lpi_state;
 934
 935         /* LPI States start at index 3 */
 936         for (loop = 3; state_idx <= pkg_count; loop++, state_idx++, lpi_state++) {
 937                 union acpi_object *element, *pkg_elem, *obj;
 938
 939                 element = &lpi_data->package.elements[loop];
 940                 if (element->type != ACPI_TYPE_PACKAGE || element->package.count < 7)
 941                         continue;
 942
 943                 pkg_elem = element->package.elements;
 944
 945                 obj = pkg_elem + 6;
 946                 if (obj->type == ACPI_TYPE_BUFFER) {
 947                         struct acpi_power_register *reg;
 948
 949                         reg = (struct acpi_power_register *)obj->buffer.pointer;
 950                         if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
 951                             reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE)
 952                                 continue;
 953
 954                         lpi_state->address = reg->address;
 955                         lpi_state->entry_method =
 956                                 reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE ?
 957                                 ACPI_CSTATE_FFH : ACPI_CSTATE_SYSTEMIO;
 958                 } else if (obj->type == ACPI_TYPE_INTEGER) {
 959                         lpi_state->entry_method = ACPI_CSTATE_INTEGER;
 960                         lpi_state->address = obj->integer.value;
 961                 } else {
 962                         continue;
 963                 }
 964
 965                 /* elements[7,8] skipped for now i.e. Residency/Usage counter*/
 966
 967                 obj = pkg_elem + 9;
 968                 if (obj->type == ACPI_TYPE_STRING)
 969                         strscpy(lpi_state->desc, obj->string.pointer,
 970                                 ACPI_CX_DESC_LEN);
 971
 972                 lpi_state->index = state_idx;
 973                 if (obj_get_integer(pkg_elem + 0, &lpi_state->min_residency)) {
 974                         pr_debug("No min. residency found, assuming 10 us\n");
 975                         lpi_state->min_residency = 10;
 976                 }
 977
 978                 if (obj_get_integer(pkg_elem + 1, &lpi_state->wake_latency)) {
 979                         pr_debug("No wakeup residency found, assuming 10 us\n");
 980                         lpi_state->wake_latency = 10;
 981                 }
 982
 983                 if (obj_get_integer(pkg_elem + 2, &lpi_state->flags))
 984                         lpi_state->flags = 0;
 985
 986                 if (obj_get_integer(pkg_elem + 3, &lpi_state->arch_flags))
 987                         lpi_state->arch_flags = 0;
 988
 989                 if (obj_get_integer(pkg_elem + 4, &lpi_state->res_cnt_freq))
 990                         lpi_state->res_cnt_freq = 1;
 991
 992                 if (obj_get_integer(pkg_elem + 5, &lpi_state->enable_parent_state))
 993                         lpi_state->enable_parent_state = 0;
 994         }
 995
 996         acpi_handle_debug(handle, "Found %d power states\n", state_idx);
 997 end:
 998         kfree(buffer.pointer);
 999         return ret;
1000 }
1001
1002 /*
1003  * flat_state_cnt - the number of composite LPI states after the process of flattening
1004  */
1005 static int flat_state_cnt;
1006
1007 /**
1008  * combine_lpi_states - combine local and parent LPI states to form a composite LPI state
1009  *
1010  * @local: local LPI state
1011  * @parent: parent LPI state
1012  * @result: composite LPI state
1013  */
1014 static bool combine_lpi_states(struct acpi_lpi_state *local,
1015                                struct acpi_lpi_state *parent,
1016                                struct acpi_lpi_state *result)
1017 {
1018         if (parent->entry_method == ACPI_CSTATE_INTEGER) {
1019                 if (!parent->address) /* 0 means autopromotable */
1020                         return false;
1021                 result->address = local->address + parent->address;
1022         } else {
1023                 result->address = parent->address;
1024         }
1025
1026         result->min_residency = max(local->min_residency, parent->min_residency);
1027         result->wake_latency = local->wake_latency + parent->wake_latency;
1028         result->enable_parent_state = parent->enable_parent_state;
1029         result->entry_method = local->entry_method;
1030
1031         result->flags = parent->flags;
1032         result->arch_flags = parent->arch_flags;
1033         result->index = parent->index;
1034
1035         strscpy(result->desc, local->desc, ACPI_CX_DESC_LEN);
1036         strlcat(result->desc, "+", ACPI_CX_DESC_LEN);
1037         strlcat(result->desc, parent->desc, ACPI_CX_DESC_LEN);
1038         return true;
1039 }
1040
1041 #define ACPI_LPI_STATE_FLAGS_ENABLED                    BIT(0)
1042
1043 static void stash_composite_state(struct acpi_lpi_states_array *curr_level,
1044                                   struct acpi_lpi_state *t)
1045 {
1046         curr_level->composite_states[curr_level->composite_states_size++] = t;
1047 }
1048
1049 static int flatten_lpi_states(struct acpi_processor *pr,
1050                               struct acpi_lpi_states_array *curr_level,
1051                               struct acpi_lpi_states_array *prev_level)
1052 {
1053         int i, j, state_count = curr_level->size;
1054         struct acpi_lpi_state *p, *t = curr_level->entries;
1055
1056         curr_level->composite_states_size = 0;
1057         for (j = 0; j < state_count; j++, t++) {
1058                 struct acpi_lpi_state *flpi;
1059
1060                 if (!(t->flags & ACPI_LPI_STATE_FLAGS_ENABLED))
1061                         continue;
1062
1063                 if (flat_state_cnt >= ACPI_PROCESSOR_MAX_POWER) {
1064                         pr_warn("Limiting number of LPI states to max (%d)\n",
1065                                 ACPI_PROCESSOR_MAX_POWER);
1066                         pr_warn("Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
1067                         break;
1068                 }
1069
1070                 flpi = &pr->power.lpi_states[flat_state_cnt];
1071
1072                 if (!prev_level) { /* leaf/processor node */
1073                         memcpy(flpi, t, sizeof(*t));
1074                         stash_composite_state(curr_level, flpi);
1075                         flat_state_cnt++;
1076                         continue;
1077                 }
1078
1079                 for (i = 0; i < prev_level->composite_states_size; i++) {
1080                         p = prev_level->composite_states[i];
1081                         if (t->index <= p->enable_parent_state &&
1082                             combine_lpi_states(p, t, flpi)) {
1083                                 stash_composite_state(curr_level, flpi);
1084                                 flat_state_cnt++;
1085                                 flpi++;
1086                         }
1087                 }
1088         }
1089
1090         kfree(curr_level->entries);
1091         return 0;
1092 }
1093
1094 int __weak acpi_processor_ffh_lpi_probe(unsigned int cpu)
1095 {
1096         return -EOPNOTSUPP;
1097 }
1098
1099 static int acpi_processor_get_lpi_info(struct acpi_processor *pr)
1100 {
1101         int ret, i;
1102         acpi_status status;
1103         acpi_handle handle = pr->handle, pr_ahandle;
1104         struct acpi_device *d = NULL;
1105         struct acpi_lpi_states_array info[2], *tmp, *prev, *curr;
1106
1107         /* make sure our architecture has support */
1108         ret = acpi_processor_ffh_lpi_probe(pr->id);
1109         if (ret == -EOPNOTSUPP)
1110                 return ret;
1111
1112         if (!osc_pc_lpi_support_confirmed)
1113                 return -EOPNOTSUPP;
1114
1115         if (!acpi_has_method(handle, "_LPI"))
1116                 return -EINVAL;
1117
1118         flat_state_cnt = 0;
1119         prev = &info[0];
1120         curr = &info[1];
1121         handle = pr->handle;
1122         ret = acpi_processor_evaluate_lpi(handle, prev);
1123         if (ret)
1124                 return ret;
1125         flatten_lpi_states(pr, prev, NULL);
1126
1127         status = acpi_get_parent(handle, &pr_ahandle);
1128         while (ACPI_SUCCESS(status)) {
1129                 d = acpi_fetch_acpi_dev(pr_ahandle);
1130                 if (!d)
1131                         break;
1132
1133                 handle = pr_ahandle;
1134
1135                 if (strcmp(acpi_device_hid(d), ACPI_PROCESSOR_CONTAINER_HID))
1136                         break;
1137
1138                 /* can be optional ? */
1139                 if (!acpi_has_method(handle, "_LPI"))
1140                         break;
1141
1142                 ret = acpi_processor_evaluate_lpi(handle, curr);
1143                 if (ret)
1144                         break;
1145
1146                 /* flatten all the LPI states in this level of hierarchy */
1147                 flatten_lpi_states(pr, curr, prev);
1148
1149                 tmp = prev, prev = curr, curr = tmp;
1150
1151                 status = acpi_get_parent(handle, &pr_ahandle);
1152         }
1153
1154         pr->power.count = flat_state_cnt;
1155         /* reset the index after flattening */
1156         for (i = 0; i < pr->power.count; i++)
1157                 pr->power.lpi_states[i].index = i;
1158
1159         /* Tell driver that _LPI is supported. */
1160         pr->flags.has_lpi = 1;
1161         pr->flags.power = 1;
1162
1163         return 0;
1164 }
1165
1166 int __weak acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
1167 {
1168         return -ENODEV;
1169 }
1170
1171 /**
1172  * acpi_idle_lpi_enter - enters an ACPI any LPI state
1173  * @dev: the target CPU
1174  * @drv: cpuidle driver containing cpuidle state info
1175  * @index: index of target state
1176  *
1177  * Return: 0 for success or negative value for error
1178  */
1179 static int acpi_idle_lpi_enter(struct cpuidle_device *dev,
1180                                struct cpuidle_driver *drv, int index)
1181 {
1182         struct acpi_processor *pr;
1183         struct acpi_lpi_state *lpi;
1184
1185         pr = __this_cpu_read(processors);
1186
1187         if (unlikely(!pr))
1188                 return -EINVAL;
1189
1190         lpi = &pr->power.lpi_states[index];
1191         if (lpi->entry_method == ACPI_CSTATE_FFH)
1192                 return acpi_processor_ffh_lpi_enter(lpi);
1193
1194         return -EINVAL;
1195 }
1196
1197 static int acpi_processor_setup_lpi_states(struct acpi_processor *pr)
1198 {
1199         int i;
1200         struct acpi_lpi_state *lpi;
1201         struct cpuidle_state *state;
1202         struct cpuidle_driver *drv = &acpi_idle_driver;
1203
1204         if (!pr->flags.has_lpi)
1205                 return -EOPNOTSUPP;
1206
1207         for (i = 0; i < pr->power.count && i < CPUIDLE_STATE_MAX; i++) {
1208                 lpi = &pr->power.lpi_states[i];
1209
1210                 state = &drv->states[i];
1211                 snprintf(state->name, CPUIDLE_NAME_LEN, "LPI-%d", i);
1212                 strscpy(state->desc, lpi->desc, CPUIDLE_DESC_LEN);
1213                 state->exit_latency = lpi->wake_latency;
1214                 state->target_residency = lpi->min_residency;
1215                 state->flags |= arch_get_idle_state_flags(lpi->arch_flags);
1216                 if (i != 0 && lpi->entry_method == ACPI_CSTATE_FFH)
1217                         state->flags |= CPUIDLE_FLAG_RCU_IDLE;
1218                 state->enter = acpi_idle_lpi_enter;
1219                 drv->safe_state_index = i;
1220         }
1221
1222         drv->state_count = i;
1223
1224         return 0;
1225 }
1226
1227 /**
1228  * acpi_processor_setup_cpuidle_states- prepares and configures cpuidle
1229  * global state data i.e. idle routines
1230  *
1231  * @pr: the ACPI processor
1232  */
1233 static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
1234 {
1235         int i;
1236         struct cpuidle_driver *drv = &acpi_idle_driver;
1237
1238         if (!pr->flags.power_setup_done || !pr->flags.power)
1239                 return -EINVAL;
1240
1241         drv->safe_state_index = -1;
1242         for (i = ACPI_IDLE_STATE_START; i < CPUIDLE_STATE_MAX; i++) {
1243                 drv->states[i].name[0] = '\0';
1244                 drv->states[i].desc[0] = '\0';
1245         }
1246
1247         if (pr->flags.has_lpi)
1248                 return acpi_processor_setup_lpi_states(pr);
1249
1250         return acpi_processor_setup_cstates(pr);
1251 }
1252
1253 /**
1254  * acpi_processor_setup_cpuidle_dev - prepares and configures CPUIDLE
1255  * device i.e. per-cpu data
1256  *
1257  * @pr: the ACPI processor
1258  * @dev : the cpuidle device
1259  */
1260 static int acpi_processor_setup_cpuidle_dev(struct acpi_processor *pr,
1261                                             struct cpuidle_device *dev)
1262 {
1263         if (!pr->flags.power_setup_done || !pr->flags.power || !dev)
1264                 return -EINVAL;
1265
1266         dev->cpu = pr->id;
1267         if (pr->flags.has_lpi)
1268                 return acpi_processor_ffh_lpi_probe(pr->id);
1269
1270         return acpi_processor_setup_cpuidle_cx(pr, dev);
1271 }
1272
1273 static int acpi_processor_get_power_info(struct acpi_processor *pr)
1274 {
1275         int ret;
1276
1277         ret = acpi_processor_get_lpi_info(pr);
1278         if (ret)
1279                 ret = acpi_processor_get_cstate_info(pr);
1280
1281         return ret;
1282 }
1283
1284 int acpi_processor_hotplug(struct acpi_processor *pr)
1285 {
1286         int ret = 0;
1287         struct cpuidle_device *dev;
1288
1289         if (disabled_by_idle_boot_param())
1290                 return 0;
1291
1292         if (!pr->flags.power_setup_done)
1293                 return -ENODEV;
1294
1295         dev = per_cpu(acpi_cpuidle_device, pr->id);
1296         cpuidle_pause_and_lock();
1297         cpuidle_disable_device(dev);
1298         ret = acpi_processor_get_power_info(pr);
1299         if (!ret && pr->flags.power) {
1300                 acpi_processor_setup_cpuidle_dev(pr, dev);
1301                 ret = cpuidle_enable_device(dev);
1302         }
1303         cpuidle_resume_and_unlock();
1304
1305         return ret;
1306 }
1307
1308 int acpi_processor_power_state_has_changed(struct acpi_processor *pr)
1309 {
1310         int cpu;
1311         struct acpi_processor *_pr;
1312         struct cpuidle_device *dev;
1313
1314         if (disabled_by_idle_boot_param())
1315                 return 0;
1316
1317         if (!pr->flags.power_setup_done)
1318                 return -ENODEV;
1319
1320         /*
1321          * FIXME:  Design the ACPI notification to make it once per
1322          * system instead of once per-cpu.  This condition is a hack
1323          * to make the code that updates C-States be called once.
1324          */
1325
1326         if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) {
1327
1328                 /* Protect against cpu-hotplug */
1329                 cpus_read_lock();
1330                 cpuidle_pause_and_lock();
1331
1332                 /* Disable all cpuidle devices */
1333                 for_each_online_cpu(cpu) {
1334                         _pr = per_cpu(processors, cpu);
1335                         if (!_pr || !_pr->flags.power_setup_done)
1336                                 continue;
1337                         dev = per_cpu(acpi_cpuidle_device, cpu);
1338                         cpuidle_disable_device(dev);
1339                 }
1340
1341                 /* Populate Updated C-state information */
1342                 acpi_processor_get_power_info(pr);
1343                 acpi_processor_setup_cpuidle_states(pr);
1344
1345                 /* Enable all cpuidle devices */
1346                 for_each_online_cpu(cpu) {
1347                         _pr = per_cpu(processors, cpu);
1348                         if (!_pr || !_pr->flags.power_setup_done)
1349                                 continue;
1350                         acpi_processor_get_power_info(_pr);
1351                         if (_pr->flags.power) {
1352                                 dev = per_cpu(acpi_cpuidle_device, cpu);
1353                                 acpi_processor_setup_cpuidle_dev(_pr, dev);
1354                                 cpuidle_enable_device(dev);
1355                         }
1356                 }
1357                 cpuidle_resume_and_unlock();
1358                 cpus_read_unlock();
1359         }
1360
1361         return 0;
1362 }
1363
1364 static int acpi_processor_registered;
1365
1366 int acpi_processor_power_init(struct acpi_processor *pr)
1367 {
1368         int retval;
1369         struct cpuidle_device *dev;
1370
1371         if (disabled_by_idle_boot_param())
1372                 return 0;
1373
1374         acpi_processor_cstate_first_run_checks();
1375
1376         if (!acpi_processor_get_power_info(pr))
1377                 pr->flags.power_setup_done = 1;
1378
1379         /*
1380          * Install the idle handler if processor power management is supported.
1381          * Note that we use previously set idle handler will be used on
1382          * platforms that only support C1.
1383          */
1384         if (pr->flags.power) {
1385                 /* Register acpi_idle_driver if not already registered */
1386                 if (!acpi_processor_registered) {
1387                         acpi_processor_setup_cpuidle_states(pr);
1388                         retval = cpuidle_register_driver(&acpi_idle_driver);
1389                         if (retval)
1390                                 return retval;
1391                         pr_debug("%s registered with cpuidle\n",
1392                                  acpi_idle_driver.name);
1393                 }
1394
1395                 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1396                 if (!dev)
1397                         return -ENOMEM;
1398                 per_cpu(acpi_cpuidle_device, pr->id) = dev;
1399
1400                 acpi_processor_setup_cpuidle_dev(pr, dev);
1401
1402                 /* Register per-cpu cpuidle_device. Cpuidle driver
1403                  * must already be registered before registering device
1404                  */
1405                 retval = cpuidle_register_device(dev);
1406                 if (retval) {
1407                         if (acpi_processor_registered == 0)
1408                                 cpuidle_unregister_driver(&acpi_idle_driver);
1409                         return retval;
1410                 }
1411                 acpi_processor_registered++;
1412         }
1413         return 0;
1414 }
1415
1416 int acpi_processor_power_exit(struct acpi_processor *pr)
1417 {
1418         struct cpuidle_device *dev = per_cpu(acpi_cpuidle_device, pr->id);
1419
1420         if (disabled_by_idle_boot_param())
1421                 return 0;
1422
1423         if (pr->flags.power) {
1424                 cpuidle_unregister_device(dev);
1425                 acpi_processor_registered--;
1426                 if (acpi_processor_registered == 0)
1427                         cpuidle_unregister_driver(&acpi_idle_driver);
1428
1429                 kfree(dev);
1430         }
1431
1432         pr->flags.power_setup_done = 0;
1433         return 0;
1434 }